Could you elaborate? Where is it missing support for Python? It just generates TLS certs for local use, and where would Cygwin, npm (a package manager), and Emacs (a text editor) even figure in any of this?

I guess this is mostly for generating localhost certs, that was not what I thought you needed this for. I was listing stuff that is a problem with running your own CA, so mainly if you are unlucky enough to be behind a enterprise proxy. I.e. how to import trusted certs everywhere.

I can not remember how and where you need to install these certs, but it just about finding where different applications store their trust stores. Lots of them have their own solutions.

Npm has an option in the config that allow you to choose your own ca location.

That has little to do with supporting specific languages and environments though, and more to do with those languages not have a good method to do CA installation. I have no idea about Node.js, but Python will just use the regular trust store for the OS, because it's all just OpenSSL under the hood.

Your problem isn't with mkcert and mkcert isn't missing support for anything, but with there not being a good, universal way to manage trust stores. That's an independent issue that mkcert can't fix.